temperamental

1 frequently influenced by moods and especially bad moods one of those temperamental actresses who can make life difficult for everyone around her Synonyms moodyRelated Words capricious, changeable, changeful, fickle, fluctuating, fluid, freakish, impulsive, inconstant, mercurial, mutable, uncertain, unsettled, unstable, unsteady, variable, volatile, whimsical; pouty, sulky; choleric, crabby, cranky, cross, crotchety, grouchy, grumpy, irascible, irritable, peevish, petulant, quick-tempered, short-tempered, snappish, snippety, snippy, testy, waspishNear Antonyms equable, even; immutable, inflexible, invariable, unalterable, unchangeable; changeless, constant, settled, stable, steady, unchanging

2 likely to change frequently, suddenly, or unexpectedly stock prices have been pretty temperamental lately, often fluctuating wildly Synonyms capricious, changeable, changeful, flickery, fluctuating, fluid, inconsistent, inconstant, mercurial, mutable, skittish, fickle, uncertain, unpredictable, unsettled, unstable, unsteady, variable, volatileRelated Words aimless, arbitrary, desultory, erratic, haphazard, hit-or-miss, irregular, random, scattered, slapdash, stray; ambivalent, hesitating, shaky, shilly-shally, shilly-shallying, vacillating, wavering; dicey, undependable, unreliable, untrustworthy; adaptable, mobile, protean, versatileNear Antonyms equable, even, uniform; abiding, durable, lasting, permanent, persistent; dependable, reliable, sure, tried, tried-and-true, true, trustworthy, trustyAntonyms certain, changeless, constant, immutable, invariable, predictable, settled, stable, stationary, steady, unchangeable, unchanging, unvarying